Describe the initiation and control of heart beat in human.
- Initiation occurs from the sino-artrio node (SAN) the peacemaker; from the SAN waves of excitation spread across both atria; causing them to contract at the same time.
- From the atria excitation reach the atrio-ventricular node (AVN); and then spread to purkinje fibre/ purkinje tissue via the bundle of His; from where they spread across both ventricles causing them to contract as a unit. ANV function to delay the spreading of impulses to the ventricle ensuring that atria contract before the ventricles.
- Contraction of the heart is accelerated by sympathetic nerves and slowed by the vagus nerves
CATEGORIES Bio Questions and answers
TAGS Dr. Bbosa Science
